MILES. That's right, Miles Davis. This music--Tony William's, John McLaughlin's, Chick Corea's, Herbie Hancock's, Joe Zawinul's--is his music and these men are his sons. All have done some time with Miles--the late, post-In a Silent Way Miles, the Miles who claims the influence of Sly Stone--and owing to their own ambitions and Miles's idiosyncracies, have since gone out on their own. The result is a music of distinct generations, like later San Francisco rock. But unlike those rock bands, who finally managed to develop reasonably unique personae, Miles's offspring have retained, in varying degrees, their mentor's stamp. Miles, when he talks to anybody, tends to grab inspirational credit (at the very least) for himself. How much more credit he deserves is debatable. But let Ralph J. Gleason sum up the whole question: "And in contemporary music Miles defines the terms. That's all. It's his turf."

With a pedigree like this, it takes a lot of chutzpah to call this Jazz-Rock. But it is: Rather than laying insipid horn charts over standard rock and giving it the name, rock's emphasis on rhythm has been injected into jazz. Enter Miles. And the rest, as they say, is history. The six ensembles that have resulted from Miles's own experiments form a mini-spectrum making up one end of a larger spectrum of all jazz. At the rock end of the small one lies The Mahavishnu Orchestra. Zawinul's Weather Report, from what little I've heard, seems a bit ethereal. Herbie Hancock's music is similar to what Miles himself is doing now. And Tony Williams's old Lifetime added a harsh virtuosity that set it apart from McLaughlin's more lyrical intensity, while retaining the solid rhythm section of good rock music. Chick Corea? Well, his band is...different.

But it's a subtle difference--you'll have to see it to appreciate it. Because the listener is first confronted with a host of similarities between Corea's Return to Forever and McLaughlin's Mahavishnu Orchestra. For one thing, there is an emphasis on individual, yet simultaneous virtuosity--an easy semantic way to take note of the disciplined nature of both music and musicians. Each rests securely on a foundation provided by the rhythm section (In fact, bassist Stan Clarke is arguably Return to Forever's best musician). On record, these similarities are enhanced--certain themes and often whole passages will simply sound the same. Onstage, though, all similarities just fall away.

The first thing you notice about Chick Corea's piano playing is the extent of his source material. He has a vast command of his musical resources--styles, phrases and even methods of attack. And as his Sanders Theater performance developed some of those resources recurred. Much of Corea's music has a distinct Spanish influence. Nothing tangible, mind you, it's more a question of "feel." My notes on this show are full of references to "latin style" riffs or themes. A new tune, called "Sometime Ago" moved through several varied themes and each had a distinctly Spanish/Latin/South American tint. The first band, also called Return to Forever, had that same tint--reed man Joe Farrell, singer Flora Purim, and percussionist Airto Moreira were three-fourths of a band that lived its only album title--Light as a Feather.

This band is louder. And possibly less assuming. The first group had its self-indulgences--Purim and Airto occasionally turned the band into an immensely talented Brasil '66. (And this may be what I mean by Latin influences). The outfit that showed up at Sanders has an album, Hymn to the Seventh Galaxy, and all those Mahavishnu comparisons. But it wasn't the same. This band is subdued, even sedate. One t-shirt. No dashikis. Corea himself is dressed in late period St. Grottlesex. Solid introductions. Then seven-eight fingersnaps and "Hymn to the Seventh Galaxy" seems half over. "Hymn" is basic Return to Forever, a good chance to define the group's specifics. This music is thematic; unlike most jazz, there is not a great deal of room for improvisation. In concert the group walks a tight line, moving smoothly from theme to brief improvisation to transition to new theme.

At the same time, there was a good deal of inspired soloing, from guitarist Bill Connors and Corea. Connors has developed a unique hybrid sound, one that draws equally from the last five years or so of rock guitar playing. He has a very heavy tone, almost ponderous and always close to the listener; the result of combined use of sustain and vibrato from the usual bank of foot switches filtered through a slightly open wah-wah pedal. You can hear shades of everyone from Eric Clapton to John McLaughlin. His solos were short, to maintain a structural balance, but beautifully constructed out of soaring lines and tasteful phrases. Connors has a subdued sense of attack, preferring not to bludgeon a solo, and really playing at his best on the complex themes that are the heart of each piece. Themes that are a little more than themes, intricate in timing and sycopation, barely coherent at a first listen. Connors and Corea are able to unite in both tone and intensity for a very full total sound, a synthesizer sound.

COREA's strongest point is persistent use of the synthesizer as an extension of the piano, rather than as a gimmick. He uses it without wasting its potential and also without abusing it. But the core of any discussion of the man is his range. Corea absorbs and transmits ideas on the run. "Captain Senor Mouse" had that Latin infusion of style and tone, a lightness of attack and a notion of exploration. The feeling, finally, is that his piano work was nothing more than a dance through a field of potential notes, with stops at notes chosen randomly in an unconscious pattern. He deals in dialogues as well. He and Bill Connors matched phrases, tones, intensities, even notes throughout "Space Circus." He can even approach the night club intimacy of an Ahmad Jamal.

The byword was a consistent brilliance. Good moments flowed like good frames in a film: Corea's recreation of a grandfather clock's movement in "Children's song #1;" an integrated drum solo, drums laid over the bass line for the first time in my memory; Stan Clarke's bass solo in "Bass Folk Song," and all his work on acoustic bass. Clarke plays bass as an equal member, not as a supporter. He attacks a solo from the viewpoint of a lead instrument, rather than expanding techniques of support. And there was Bill Connors's nice classically acoustic intro to "Sometime Ago."

Now that the Mahavishnu Orchestra has collapsed, some sort of mantle must fall to Return to Forever. Miles is unreliable, the others too esoteric. Corea has the answer; controlled improvisation, and a foundation that's as solid as rock.